Can you be so good at chess that you never lose [I mean being that dominant]
We believe stockfish 10 will never lose to a human player no matter how good the person is.
Can one train to that level to be almost impossible to beat?
What do you believe would happen if 3 elite GM's had 8 weeks to plan each move?
each move of what?
"stockfish 10 will never lose to a [human player]"
"stockfish 10 will never lose to a [3 elite GM's with 8 weeks to plan each move]"
"We believe stockfish 10 will never lose to a human player no matter how good the person is.
Can one train to that level to be almost impossible to beat?"
You're asking whether a human can train to a level that "we believe" no human can train to. What is the point of such a contradictory question?
If the the bunch GMs don't use engines they don't stand a chance. They are mincemeat.
If the grandmasters keep the position closed they probably can draw.
Also remember that GMs are still human..... Many people talk about how dominant Magnus Carlsen is but he can still lose games of course. IMO that's the main difference between computers and human players. Off days, distractions, random things can lower a human's performance, whereas a computer will just keep crunching numbers, because they don't need to think about much else, heck, they can't.
capablanca is never beaten (as far as i know)
no capablanca lost 36 games
